The chainsaw is an extremely efficient and versatile tool which can be used by the individual for small cutting tasks such as cutting firewood or clearing brush. Chainsaws are also used professionally by those in the lumber industry for clearing and for cutting timber and large trees. Chainsaws are also used by firefighters, emergency workers and others.
The basic chainsaw may be powered either by a small engine such as a two-stroke, air-cooled engine or, in some applications, may be powered an electric motor. The conventional chainsaw has a shaft which drives a sprocket which may be connected to the shaft through a clutch. An endless chain is driven by the sprocket and is guided along a slot in an elongate chainsaw bar. The conventional chain has a plurality of links including cutting links and raker teeth which control the depth of the cut.
The cutting teeth and raker teeth project outwardly from the bar. The drive links extend downwardly and ride in a longitudinal channel or groove in the chainsaw bar. The teeth are connected by connecting links at pins or rivets to allow the chain to be continuously driven in the track or channel by the engagement of the drive links with the sprocket.
Several problems exist with conventional chains. Once the chain cutting teeth become dull or damaged as the result of use or, perhaps, encountering a hard object such as a nail or a rock, the chain must be removed, the teeth sharpened and the chain replaced on the saw. When this occurs, some users, particularly less experienced users, often reinstall the chain backwards so that the teeth will not effectively cut. Further the procedure of having to remove the chain and either sharpen the chain or take it to a facility for sharpening, requires substantial time and interruption of the task at hand.